Not wanting to get into another argument here, just gathering facts.
At the very minimum never use an old split cotter pin twice.
Spend more money if it makes you happy.
I once disassembled a Mark VII engine and found broken split cotter pins in the sump, but every single one of them had twists and plier marks, clear evidence that they had been used several times.
I also disassembled my 120, a 140 and my Mark V engines and all the split cotter pins were installed correctly and in perfect condition. I of course installed new, same size, same method.
Jaguar used them from the 1930s until 1968, about 316,000 engines or 3,700,000 pins. Properly sized and installed they don’t fall off.
The advantage of 12 point nuts is fast assembly; on the production line time is money.
Or peace of mind.